Interim Executive Director of the MTA Helena Williams said she expected the majority of the Throgs Neck Bridge’s lanes to be open by rush hour Friday evening after an early morning fire forced officials to close the major thoroughfare that connects the Queens and the Bronx for more than six hours, leaving thousands of drivers stuck in traffic and causing major delays on the Cross Island Parkway and Long Island Expressway.

More than 130 firefighters from 33 units battled the blaze that broke out at 4:58 a.m. Friday morning and became a third-alarm fire a little after 6 a.m., a spokesman for the FDNY said at midday. Three firefighters and two MTA Bridges and Tunnels officers sustained minor injuries and were sent to New York Hospital Queens, an official said.

Heavy timbers located directly below the bridge that had been used as a safety platform for construction workers caught fire, according to FDNY Assistant Chief James Esposito. Esposito said they were still investigating the cause of the blaze.

The Throgs Neck was closed by 6:30 a.m. and the fire was extinguished after noon, officials said. The bridge’s Queens-bound lanes were reopened after 1 p.m., and all but one of the northbound lanes were expected to be opened by Friday evening. No trucks will be allowed to drive northbound on the bridge, according to the MTA.

Esposito said it was especially difficult for firefighters to reach the blaze due to its position directly under the bridge, and many of those battling the blaze worked in safety harnesses tethered to the side of the bridge.

Williams said the MTA and the FDNY would assess the damage to the bridge and develop a repair plan, although she gave no time line for those measures. Williams emphasized the bridge was safe enough for travel Friday evening.

“Safety is our highest priority,” Williams said. “I can assure you we would not open lanes if the bridge was not safe.”

Though officials did not know exactly how many drivers were affected by the bridge’s closing, they said it was thousands. More than 100,000 drivers use the Throgs Neck Bridge on a typical weekday, according to the MTA.

While the bridge was closed, traffic was diverted across the Whitestone and the Robert F. Kennedy Bridge, formerly known as the Triborough.

Bayside resident Jeff Sturza said he had to sit for four hours in bumper-to-bumper traffic while driving from Queens to Brooklyn Friday morning.

“I know New York City has traffic, but this traffic was unbearable,” said Sturza, who awoke early Friday morning to the sound of police helicopters flying near his home at Bayside Terrace.